US4432242A - Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator - Google Patents

Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator Download PDF

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Publication number
US4432242A
US4432242A US06/329,539 US32953981A US4432242A US 4432242 A US4432242 A US 4432242A US 32953981 A US32953981 A US 32953981A US 4432242 A US4432242 A US 4432242A
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United States
Prior art keywords
vibration signal
switches
vortex shedding
vibration
signal
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Expired - Lifetime
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US06/329,539
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English (en)
Inventor
William L. Thompson
Michael S. Willey
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Elsag International BV
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Babcock and Wilcox Co
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Assigned to BABCOCK & WILCOX COMPANY,THE reassignment BABCOCK & WILCOX COMPANY,THE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: THOMPSON, WILLIAM L., WILLEY, MICHAEL S.
Priority to US06/329,539 priority Critical patent/US4432242A/en
Priority to CA000417250A priority patent/CA1182307A/en
Priority to DE8282306580T priority patent/DE3275403D1/de
Priority to EP82306580A priority patent/EP0084232B1/en
Priority to JP57215649A priority patent/JPS58154620A/ja
Publication of US4432242A publication Critical patent/US4432242A/en
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Assigned to BABCOCK & WILCOX TRACY POWER, INC., A CORP. OF DE reassignment BABCOCK & WILCOX TRACY POWER, INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BABCOCK & WILCOX COMPANY, THE, A CORP. OF DE
Assigned to ELSAG INTERNATIONAL B.V., A CORP. OF THE NETHERLANDS reassignment ELSAG INTERNATIONAL B.V., A CORP. OF THE NETHERLANDS ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BABCOCK & WILCOX TRACY POWER, INC., A CORP. OF DE
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/32—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow using swirl flowmeters
    • G01F1/325—Means for detecting quantities used as proxy variables for swirl
    • G01F1/3287—Means for detecting quantities used as proxy variables for swirl circuits therefor

Definitions

  • the present invention relates in general to vortex shedding flowmeter circuits and in particular to a new and useful arrangement for reducing vibration noise and sensitivity in vortex shedding flowmeter sensor circuits.
  • vortex shedding transmitters are particularly sensitive to vibrations. Such vibrations are sometimes misinterpreted as the vortex shedding frequency or at least represent noise and obstruction to receiving the vortex shedding frequency.
  • the present invention provides for circuitry which processes a vibration signal and subtracts it from the vortex shedding frequency signal to provide a shedding frequency signal with reduced or eliminated noise.
  • an object of the present invention is to provide a separate vibration sensor with preamp for sensing the vibration in the flow stream.
  • a vibration signal is provided through a phase lock loop and counter to a channel multiplexer circuit which selectively and sequentially applies a voltage from different sequential parts of the vibration signal to a plurality of capacitors.
  • the vortex sensor signal is provided through the multiplexer circuitry wherein the vibration signal at each instant is substracted from the vortex shedding frequency signal to provide a substantially noise reduced output signal for further amplification.
  • a further object of the invention is to provide a circuit for producing vibration sensitivity and vortex shedding flowmeters which is simple in design and economical to manufacture.
  • FIG. 1 is a block and schematic diagram of the circuit according to the invention.
  • FIG. 2 is a wave form diagram showing the application of voltages to various capacitors of the circuit
  • FIG. 1 the invention embodied therein in FIG. 1 comprises a vortex sensor 10 and preamp 12 for amplifying a vortex shedding frequency from the vortex shedder. Also included is a vibration sensor 14 and a preamp for the vibration signal 16.
  • a connecting line 20 is connected across the output lines 22 and 24 respectively of the vortex sensor and vibration sensor preamps.
  • a selector switch S a is manually operable in a known manner to select one of the output lines 20 or 24.
  • the output line 24 from vibration sensor 14 is shown connected.
  • a phase lock loop 30, for example, CA4046B is connected to the output 24 of the vibration sensor which maintains a signal in known fashion in case the signal disappears.
  • the phase lock loop circuit locks into the vibration signal and generates a control signal for tracking a notch filter that is in synchronism with the vibration signal component vibration sensor 14.
  • the vibration signal is multiplied by a number n (the number of switches S 1 through S n shown in multiplexer circuit 36. This multiplication takes place in the phase lock group 30 using known circuit components.
  • phase lock loop 30 is connected to a dividing counter 32 which is for example CA4520B.
  • Counter 32 divides the signal by the value n and provides it over digital output lines 34 to the multiplexer 36.
  • the multiplexer 36 operates to sequentially close switches S 1 through S n during a single period of the vibration frequency. If there is no single vibration frequency the period is divided by the fundamental frequency or most prominent frequency component of the vibration signal.
  • Each capacitor C 1 through C n is thus supplied with a time average voltage value from the counter 32 signal during each time increment during which its corresponding switch is closed. Since the capacitors are in series with the vortex sensor signal coming from line 22, the capacitor voltage is subtracted from the vortex shedding frequency signal.
  • the multiplexer comprising the switches is exemplified by the integrated circuit multiplexer designated CD4067B.
  • one period of fundamental vibration signal 44 is shown whose voltage varies over the total period T.
  • the total period is divided by n into time increments dt.
  • the average voltage V 1 through V n for each time increment is applied to its corresponding capacitor C 1 through C n by the sequential operation of respective switches S 1 through S n .
  • the vibration in the vortex sensor apparatus induced flow is sometimes sufficiently great to produce a vibration signal in the vortex sensor itself and, when this is the case, the switch S A can be switched over to connect line 20 and provide the vibration signal to the phase lock loop circuit 30.
  • the opamp stage 40 at the output of the filter converts the vortex signal currents in the capacitors to a voltage type signal to drive the following known circuitry such as a 4-20 ma converter for a control signal (not shown).
  • the time constant of resistor R 1 and the capacitors taken individually determines the average of the signal and the band width of the notch. These are chosen typically so that 1/2 ⁇ R 1 C is less than one tenth of the vibration signal to be removed. Also this determines the lower limit of the desired vortex signal to be amplified. That is the lower cutoff will be determined by 1/2 ⁇ R 1 C where C is the value of the individual capacitors C 1 through Cn.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)
US06/329,539 1981-12-10 1981-12-10 Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator Expired - Lifetime US4432242A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US06/329,539 US4432242A (en) 1981-12-10 1981-12-10 Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator
CA000417250A CA1182307A (en) 1981-12-10 1982-12-08 Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator
DE8282306580T DE3275403D1 (en) 1981-12-10 1982-12-09 Filter circuits for reducing vibration sensitivity in vortex shedding flowmeter signal generators
EP82306580A EP0084232B1 (en) 1981-12-10 1982-12-09 Filter circuits for reducing vibration sensitivity in vortex shedding flowmeter signal generators
JP57215649A JPS58154620A (ja) 1981-12-10 1982-12-10 渦離脱形流量計信号発生器の振動感度を減少させるための同調可能なノツチフイルタ

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US06/329,539 US4432242A (en) 1981-12-10 1981-12-10 Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator

Publications (1)

Publication Number Publication Date
US4432242A true US4432242A (en) 1984-02-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
US06/329,539 Expired - Lifetime US4432242A (en) 1981-12-10 1981-12-10 Tunable notch filter for reducing vibration sensitivity for vortex shedding flowmeter generator

Country Status (5)

Country Link
US (1) US4432242A (enrdf_load_stackoverflow)
EP (1) EP0084232B1 (enrdf_load_stackoverflow)
JP (1) JPS58154620A (enrdf_load_stackoverflow)
CA (1) CA1182307A (enrdf_load_stackoverflow)
DE (1) DE3275403D1 (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990004230A1 (en) * 1988-10-14 1990-04-19 Engineering Measurements Company Signal processing method and apparatus for flowmeters
US5005425A (en) * 1988-04-16 1991-04-09 Mitsubishi Denki Kabushiki Kaisha Vortex flowmeter
US5710720A (en) * 1996-04-30 1998-01-20 Board Of Regents Of The University Of Nebraska Phase lock loop based system and method for decomposing and tracking decomposed frequency components of a signal, with application to vibration compensation system
US8820176B2 (en) 2011-01-31 2014-09-02 Krohne Messtechnik Gmbh Vortex flow meter having an inertial sensor for detecting parasitic oscillations

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63231221A (ja) * 1987-03-19 1988-09-27 Mitsubishi Electric Corp エンジンの吸気量測定装置
JPH0648351Y2 (ja) * 1988-11-14 1994-12-12 オーバル機器工業株式会社 渦流量計信号増幅回路
US8606543B2 (en) * 2010-04-30 2013-12-10 Rosemount Aerospace Inc. Method to detect angle sensor performance degradation through dither monitoring

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3709034A (en) * 1971-02-02 1973-01-09 Fischer & Porter Co Signal conditioner for recovering dominant signals from swirl-type meters
US3982434A (en) * 1975-03-14 1976-09-28 Eastech, Inc. Fluid flow signal processing circuit
US4019384A (en) * 1974-02-26 1977-04-26 Fischer & Porter Co. Digital read-out system for external-sensor vortex flowmeter
US4270391A (en) * 1979-08-24 1981-06-02 Fischer & Porter Co. Frequency-responsive filter for flowmeter transmission system

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4094194A (en) * 1977-02-14 1978-06-13 Fischer & Porter Company Sensing system for vortex-type flowmeters
US4123940A (en) * 1977-09-23 1978-11-07 Fischer & Porter Company Transmission system for vortex-shedding flowmeter
JPS55113911A (en) * 1979-02-26 1980-09-02 Nissan Motor Co Ltd Karman vortex flow meter
JPS55117323A (en) * 1979-03-02 1980-09-09 Matsushita Electric Ind Co Ltd Filter
JPS5698613A (en) * 1980-01-11 1981-08-08 Nissan Motor Co Ltd Fuel control device
US4336513A (en) * 1980-07-02 1982-06-22 Hewlett-Packard Company Hum reduction circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3709034A (en) * 1971-02-02 1973-01-09 Fischer & Porter Co Signal conditioner for recovering dominant signals from swirl-type meters
US4019384A (en) * 1974-02-26 1977-04-26 Fischer & Porter Co. Digital read-out system for external-sensor vortex flowmeter
US3982434A (en) * 1975-03-14 1976-09-28 Eastech, Inc. Fluid flow signal processing circuit
US4270391A (en) * 1979-08-24 1981-06-02 Fischer & Porter Co. Frequency-responsive filter for flowmeter transmission system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5005425A (en) * 1988-04-16 1991-04-09 Mitsubishi Denki Kabushiki Kaisha Vortex flowmeter
WO1990004230A1 (en) * 1988-10-14 1990-04-19 Engineering Measurements Company Signal processing method and apparatus for flowmeters
US5710720A (en) * 1996-04-30 1998-01-20 Board Of Regents Of The University Of Nebraska Phase lock loop based system and method for decomposing and tracking decomposed frequency components of a signal, with application to vibration compensation system
US8820176B2 (en) 2011-01-31 2014-09-02 Krohne Messtechnik Gmbh Vortex flow meter having an inertial sensor for detecting parasitic oscillations

Also Published As

Publication number Publication date
EP0084232A1 (en) 1983-07-27
DE3275403D1 (en) 1987-03-12
CA1182307A (en) 1985-02-12
JPS635686B2 (enrdf_load_stackoverflow) 1988-02-04
JPS58154620A (ja) 1983-09-14
EP0084232B1 (en) 1987-02-04

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